The black bullhead was abundant at the upper stations on each river,
especially in backwaters having mud-bottom. The species was not taken in
the mainstream of the lower and middle Neosho stations, but was taken at
the middle Neosho station in a pond that is often flooded by the river.
Although the fish was common or abundant in nearly all pools at the
upper Neosho station, it was most abundant in one pool that had a bottom
predominately of mud.
At the middle Marais des Cygnes station, 109 individuals were collected
and fin-clipped on 8, 9 and 24 July 1957. Three of the 19 marked on 8
July were recaptured in the same area on 9 July. The area was poisoned
on 13 September, 1957, and 130 black bullhead were taken, none of which
had been marked.
In 1959, 96 black bullhead were taken at the upper Neosho station (five
in Area 1 and 91 at the White Farm). In these collections, 25 were
marked (fin-clipped or dyed) and six were recaptured. Four of the six
had not left the area of capture one and two days after being released.
The fifth fish recaptured was one of five individuals that had been
displaced one pool downstream. When recaptured seven days later, this
fish had moved upstream over two steep riffles (two to three inches
deep, 75 feet and 166 feet long) past the site of original capture to
the next pool. The sixth fish, marked at the same time but returned to
the original pool, was recaptured nine days after original capture and
had moved upstream over a long riffle (two to three inches deep, 166
feet long) and a short riffle into the second pool above the original
site of its capture.
Rotenone was applied to a small (.04 acre-feet) backwater ditch having a
soft mud bottom at the upper Marais des Cygnes station on 25 July, 1957;
1526 black bullhead, one green sunfish and one white crappie were
collected. A sample of 60 bullhead averaged 4.6 inches T.L. (range 3.5
to 6.6 inches) and 540 individuals averaged .7 ounce each. These fish
probably represented the 1956 year-class.
The upper Neosho station had a large population of black bullhead,
strongly dominated by fish less than four inches T. L. (range 1.5 to 3.8
inches), in the spring of 1957. Most were approximately two inches T.
L. and probably represented the 1956 year-class. Growth, according to
length-frequency, following restoration of stream-flow, shows a regular
increase in length of this dominant 1956 year-class (Fig. 3). A scarcity
of young, especially in 1958 and 1959, is apparent in Fig. 3. This may
be due to the fact that a strong year-class usually is followed by one
or several weak year-classes. However, it more probably reflects the
fact that black bullhead are characteristically pond fish, and as such
are not so well adapted to reproduction in flowing streams as are many
other species. Metcalf (1959) found this species most abundantly in the
intermittent headwaters of Walnut River and Grouse Creek in Cowley
County, Kansas.
[Illustration: FIG. 3. Length-frequency of black bullhead
at the upper Neosho station, 1957, 1958 and 1959.]
#Pylodictis olivaris# (Rafinesque)